A color filter is used as a color face plate for a cathode-ray tube display, a photoelectric transfer element plate for copying, a filter for a single tube-type color television camera, a flat panel display using liquid crystal or a color solid camera element.
Commonly used color filters are constituted by regularly arranged primary colors of red, green and blue, however, the color filter may comprise four or more color hues, if desired. For example, a color filter for camera tube or a color filter for liquid crystal display is required to have a black pattern (black matrix) for various purposes.
Specific examples of the arrangement of red, green and blue colors include mosaic arrangement, stripe arrangement and delta arrangement, and the arrangement may be selected according to the requirement.
Conventionally known methods for producing a color filter include evaporation, dyeing, printing, pigment dispersion, electrodeposition and electrodeposition transfer of a resist. However, color filters obtained by these methods are disadvantageous in that a complicated production process is required, pinholes or scratches are readily generated, the yield is low, and accuracy is not ensured.
In order to overcome these problems, a method of producing a color filter according to an external development method (for example, JP-A-55-6342, the term "JP-A" as used herein means an "unexamined published Japanese patent application") or an internal development method (for example, JP-A-62-148952 and JP-A-62-71950), using a silver halide light-sensitive material, has been investigated. In the case of using the color filter manufactured by these methods in a liquid crystal display or other precision electron devices, a thin film comprising, for example, indium oxide-tin oxide (ITO) is deposited on the color filter and subjected to patterning by means of photolithography or the like to form a transparent electrode. In order to prevent deterioration of the color filter in this process, the color filter layer needs be previously coated with a protective film. The protective film is required to have properties such as chemicals resistance, adhesion to the color filter, coatability, transparency and scratch resistance. As the protective film having such properties, an acrylic resin (for example, JP-A-58-196506, JP-A-62-119501), a polyglycidyl methacrylate-base resin (for example, JP-A-60-216307) and an epoxy-base resin (for example, JP-A-63-131103) have been proposed.
However, it has been found that when such a protective film is applied on a color filter manufactured using a silver halide light-sensitive material, the protective film is put into contact with outside air under high humidity for a long period of time, whereby wrinkles are generated due to difference in the swelling ratio between the color filter and the protective film, and the transmittance is considerably reduced. Furthermore, the adhesion of such a protective film to the color filter may be impaired. In addition, the color filter may undergo stains or discoloration because formation of the protective film requires high temperature and much time. Thus, there is a need of improvement, in particular, a method of forming a protective film not requiring high temperature in the hardening reaction is being demanded.